underlined by me
Notice no mention of father in my "ubm". Maybe father abducted her?
I just don't think anyone abducts a child to make them feel like an unwelcome burden.
Or, maybe the man who raised her actually was her father, and she was born from an affair and neither wanted her but the mom couldn't care for her. That would make sense. And would explain both parents hostility toward her, however unfair that is.
People abduct children (babies usually) because they have a psychotic need to have a child and can't, so they steal one. Or they abduct a child to sexually abuse and hold it captive.
Neither of those things appear to be the motive here.